From a71395c7c8fdc6cd223250cd62dd995d830cb063 Mon Sep 17 00:00:00 2001
From: Andy Pan <panjf2000@gmail.com>
Date: Tue, 18 May 2021 15:43:13 +0800
Subject: [PATCH] Improve the internal spin-lock

---
 internal/spinlock.go      |  8 +++-
 internal/spinlock_test.go | 78 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 84 insertions(+), 2 deletions(-)
 create mode 100644 internal/spinlock_test.go

diff --git a/internal/spinlock.go b/internal/spinlock.go
index 16607ef..af8b55f 100644
--- a/internal/spinlock.go
+++ b/internal/spinlock.go
@@ -1,4 +1,4 @@
-// Copyright 2019 Andy Pan. All rights reserved.
+// Copyright 2019 Andy Pan & Dietoad. All rights reserved.
 // Use of this source code is governed by an MIT-style
 // license that can be found in the LICENSE file.
 
@@ -13,8 +13,12 @@ import (
 type spinLock uint32
 
 func (sl *spinLock) Lock() {
+	backoff := 1
 	for !atomic.CompareAndSwapUint32((*uint32)(sl), 0, 1) {
-		runtime.Gosched()
+		for i := 0; i < backoff; i++ {
+			runtime.Gosched()
+		}
+		backoff <<= 1
 	}
 }
 
diff --git a/internal/spinlock_test.go b/internal/spinlock_test.go
new file mode 100644
index 0000000..577037f
--- /dev/null
+++ b/internal/spinlock_test.go
@@ -0,0 +1,78 @@
+// Copyright 2021 Andy Pan & Dietoad. All rights reserved.
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+package internal
+
+import (
+	"runtime"
+	"sync"
+	"sync/atomic"
+	"testing"
+)
+
+type originSpinLock uint32
+
+func (sl *originSpinLock) Lock() {
+	for !atomic.CompareAndSwapUint32((*uint32)(sl), 0, 1) {
+		runtime.Gosched()
+	}
+}
+
+func (sl *originSpinLock) Unlock() {
+	atomic.StoreUint32((*uint32)(sl), 0)
+}
+
+func GetOriginSpinLock() sync.Locker {
+	return new(originSpinLock)
+}
+
+type backOffSpinLock uint32
+
+func (sl *backOffSpinLock) Lock() {
+	wait := 1
+	for !atomic.CompareAndSwapUint32((*uint32)(sl), 0, 1) {
+		for i := 0; i < wait; i++ {
+			runtime.Gosched()
+		}
+		wait <<= 1
+	}
+}
+
+func (sl *backOffSpinLock) Unlock() {
+	atomic.StoreUint32((*uint32)(sl), 0)
+}
+
+func GetBackOffSpinLock() sync.Locker {
+	return new(backOffSpinLock)
+}
+
+func BenchmarkMutex(b *testing.B) {
+	m := sync.Mutex{}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			m.Lock()
+			m.Unlock()
+		}
+	})
+}
+
+func BenchmarkSpinLock(b *testing.B) {
+	spin := GetOriginSpinLock()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			spin.Lock()
+			spin.Unlock()
+		}
+	})
+}
+
+func BenchmarkBackOffSpinLock(b *testing.B) {
+	spin := GetBackOffSpinLock()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			spin.Lock()
+			spin.Unlock()
+		}
+	})
+}